I'm all for keeping your units original, "BUT". Always one of those around.
When it comes to safety I have to give in.
The two prong shore power connection was replaced with the grounded connection for a very good reason.
I would suggest that you all figure out a way to install a grounded shore power connection.
If you must have the original entry port, disconnect it. I would like to suggest that you then find a hidden spot for a modern, safe shore power connection.
If this is not possible maybe a machine shop could modify the old one to accept a 3 prong connector.
Good Luck and Stay Safe.

Kevin, I am interested in swithching mine to this setup. Is there an adapter that allows you to plug that cord into a regular 110 outlet on a generator? Would that plug in at an RV campground? I'm not only new to AS but all Rv connections.

I also ended up resorting to a marinco shore power plug on our '59 tradewind. The stainless steel model #303SSEL-B seemed to match the trailer better than the plastic one. It also saved the side of the trailer when I was backing through our narrow gate!
I stopped when I heard the sound of splintering wood even though my wife was saying I had plenty of room!!! With out that honkin' Marinco SS power inlet the rear corner of the trailer would have been toast! It works fine since the mishap.

Now we use walkies talkies or our cell phones when backing into our backyard!

A previous owner updated to a residential style panel with breakers.
Paul

Seeing the recent discussions over electrical hook-ups, it dawned on me that our '55 has the original 2 prong cord (gauge unknown, maybe 12, I'm guessing 14). What do I have to do to make it safe in regards to grounding? Can I use an inline GFI on the cord? I think I will eventually end up upgrading the cord, but I have the original glass screw-in type fuses located all over the trailer. How do I address this? Suggestions? I want to play it safe on this.

The best tool for checking which wire is "hot" is called a non-contact tester. Home Depot sells them for not too much. It's a pen sized tool which clips into your shirt pocket. It will eliminate all of the guess work for you. When you depress the switch, it chirps loudly when the plastic probe gets close to your hot wire. I'm not sure if all testers work on 12 volt systems, but they can be a life saver when working with higher a/c voltages.

The best tool for checking which wire is "hot" is called a non-contact tester. Home Depot sells them for not too much. It's a pen sized tool which clips into your shirt pocket. It will eliminate all of the guess work for you. When you depress the switch, it chirps loudly when the plastic probe gets close to your hot wire. I'm not sure if all testers work on 12 volt systems, but they can be a life saver when working with higher a/c voltages.

A First post from a new Member !! Welcome to the forums Neighbor,Great to see You here !!